Passive House Is the Most Rigorous Energy Performance Standard in Common Use - and It Gets Results
The Passive House (Passivhaus) standard originated in Germany in the early 1990s and has become the most widely adopted ultra-low energy building standard in the world, with thousands of certified buildings in Europe, North America, and Australia. Unlike LEED (which is a rating system measuring performance across multiple environmental categories), Passive House focuses almost exclusively on energy performance - specifically on reducing heating and cooling loads through the quality of the building envelope and ventilation to the point where a conventional heating or cooling system is unnecessary or dramatically undersized. The ARE PPD tests Passive House as a high-performance sustainable design approach, asking candidates to understand its core principles and how they relate to conventional building design practice.
The Five Core Principles
Passive House certification requires compliance with five core design principles: (1) Superinsulation: Continuous insulation of very high R-value in all envelope assemblies. Typical wall R-values of R-30 to R-60; roof assemblies at R-60 to R-100; no thermal bridges. (2) High-performance windows: Triple-pane glazing with thermally broken frames; typical U-values of 0.10-0.15 (compared to 0.25-0.40 for conventional code-compliant windows). Windows are sized and oriented to maximize passive solar gain in winter while minimizing summer overheating. (3) Airtightness: The building enclosure must be extremely airtight - Passive House requires no more than 0.6 air changes per hour at 50 pascals of pressure (ACH50 ≤ 0.6), compared to typical new construction at 3-8 ACH50. This level of airtightness requires careful detailing and is verified by a blower door test. (4) Thermal-bridge-free construction: All connections between the insulation layer and adjacent materials must be designed to prevent conductive heat paths. Penetrations (fasteners, beam-to-wall connections, window frames) are detailed to minimize thermal bridging. (5) Heat recovery ventilation (HRV/ERV): Because the building is so airtight, mechanical ventilation is required to maintain indoor air quality. A Heat Recovery Ventilator (HRV) or Energy Recovery Ventilator (ERV) transfers heat (and in ERVs, moisture) from the exhaust air stream to the incoming fresh air stream, recovering 80-90% of the ventilation energy that would otherwise be lost.
Passive House vs. LEED
LEED is a multi-category rating system with points for energy, water, materials, site, and indoor quality. A LEED Platinum building may still have substantial energy use if it scores well in other categories. Passive House is a performance standard with a hard energy use limit - the standard requires heating demand ≤15 kWh/m²/year and total primary energy demand ≤120 kWh/m²/year (using the PHIUS or PHI standards). A Passive House building uses dramatically less energy than a typical LEED-certified building, but may not score well on LEED's site, materials, and water categories without additional design effort.
Key Exam Points
- Passive House: ultra-low energy standard; 5 principles: superinsulation, high-performance windows, airtightness, thermal bridge-free, HRV/ERV.
- Airtightness requirement: ≤ 0.6 ACH50 (verified by blower door test).
- HRV: transfers heat from exhaust to supply air; 80-90% heat recovery efficiency; required because extreme airtightness eliminates natural infiltration ventilation.
- Energy limit: heating demand ≤ 15 kWh/m²/year; total primary energy ≤ 120 kWh/m²/year.
- Passive House vs. LEED: Passive House focuses on energy performance metrics; LEED addresses multiple environmental categories.
AREprep's PPD sustainable design content covers high-performance building standards including Passive House, net-zero energy, LEED, and WELL - giving ARE PPD candidates an understanding of the full spectrum of sustainable design certification and performance standards that appear in the PPD exam's environmental design content area.
Study PPD on AREprep
AREprep's PPD flashcards and practice exams are built around the actual NCARB exam guide - so every study session targets what the exam tests.